Automatic safety switch for automotive vehicles



y 11, 1943- c. E. DEARBAUGH 2,318,989

AUTOMATIC SAFETY SWITCH FOR AUTOMOTIVE VEHICLES Filed April 7, 1941Jnventoi' Www (Ittorneg 62 lFFOKO E. OEAmm/ H.

Patented May 11, 1943 UNITED STATES PATENT OFFICE AUTOMATIC SAFETYSWITCH F OR AUTOMOTIVE VEHICLES 7 Claims.

The present invention relates broadly to automatic switches and moreparticularly to an improved safety device for automotive vehicles whichis operable, upon excessive shock to or tilting of the vehicle beyond apredetermined angle. to cut off the flow of current to the ignition andother electrical circuits associated with the motor.

Although especially designed for-automobiles, the invention is readilyadaptable to commercially flown airplanes, where the normal operatingposition of the plane is substantially constant, and in fact to any typeof vehicle powered by an internal combustion engine having an electricalignition system and which uses a volatile, highly inflammable fuel.

One of the greatest hazards attendant upon automobile collisions orupsets and airplane crashes is the danger of fire or explosion due tothe igniting of vapors of spilled gasoline which, when mixed with air inproper proportions, form a dangerously explosive gas. Ordinarily,manifolds and exhaust pipes do not become sufliciently hot to ignitegasoline, but I have found that the fires and explosions which so oftenfollow accidents are almost invariably caused by contact of the highlycombustible fumes or vapors of escaping fuel with high tension wires orshort circuits in the electrical system, or by flames from the exhaustin cases where the motor continues to operate after overturning of thevehicle.

It is therefore an important aim of my invention to provide an automaticsafety switch of novel construction and design which, when properlyinstalled in an automobile, will instantly open the electrical circuitsto the motor and stop the engine whenever the car sways or tilts to whathas been determined to be a dangerous angle, and which will cause thesecircuits to be positively and permanently broken in the event of anupset or serious collision.

Another object of the invention is the provision of an automatic switchof the above character which will insure a constant and uniform supplyof current to the motor during normal operation of the vehicle bymaintaining the electrical circuits closed during any and allnon-hazardous operating conditions.

Still another object is the provision of an automatic safety switch ofthis kind which can be completely assembled before shipping and can bereadily put into operating condition after installation without anyspecial adjustments.

Further objects and advantages will be apparent during the course of thefollowing description when taken in connection with the accompanyingdrawing.

In the drawing wherein like numerals are employed to designate likeparts throughout the same:

Fig. 1 is a vertical section through a complete switch as received fromthe factory and ready for installation;

Fig. 2 is a Vertical section through the switch after it has beeninstalled in an automobile and is ready for operation;

Fig. 3 is a section taken substantially on line 3-3 in Fig. 2;

Fig. 4 is a diagrammatic view showing the position of the mercuryreceptacle when the automobile has been tilted to a dangerous angle;

Fig. 5 is a view similar to Fig. 4 showing the position of the mercuryreceptacle when the automobile has been partially overturned; and

Fig. 6 is a section taken substantially on line 6-6 in Fig. 2.

Referring now more particularly to the drawing, wherein has beenillustrated a preferred embodiment of my invention, the letter Adesignates in its entirety an automatic safety switch adapted to beattached to the front face of a dashboard B of an automobile (Figs. 2, 3and 6). As here shown, the switch A comprises a cylindrical, outercasing ll), of metal, plastic or other desired material, within which isarranged a mercury cup" or receptacle II,

The receptacle II is supported by a pair of downwardly extending wireelectrodes l2 and I3, mounted at their upper ends in the square heads 14and I5 respectively of threaded posts I6 and I1 passing through suitableopenings in the side walls of the casing l0. Threaded upon the posts [6and I! in a manner to rigidly secure them to the casing III are nuts I8and I9 respectively, said posts and nuts being insulated from the casingby means of fiber washers or the like 20 clamped therebetween. Heldtightly against cylindrical extensions 2| and 22 of the nuts l8 and ill,by means of screws 23 and lock washers 24, are termlnals 25 and 26whereby the switch A may be interposed in the electrical circuit of theautomobile.

In forming the receptacle II a length of glass tubing is preferablyused, said tubing being bent into a substantially V shape having aflattened apex which provides a restricted passageway 2! connecting thediverging arms 28 and 29 of the V. Each of the arms 28 and 29 is bentagain as at 30 to form upwardly and inwardly directed portions 3|thereon, while a part of the edge of the tube, at either end, is turnedsharply over to form inwardly directed lips 32. The shaping of the glasstubing in this manner forms a vertically elongated receptacle having twosubstantially vertical arms or compartments 28 and 29 which are open tothe atmosphere at their upper ends and connected together at their lowerends by a restricted passageway 21 of relatively smaller cross sectionthan the arms.

In order to retain and support the receptacle ll within the casing it,each of the electrodes l2 and I3, which extend downwardly into thetubular arms 23 and 29 respectively of the receptacle, is formed with anupper, hooked section 33 which embraces one of the lips. 32, a

straight intermediate section 34 which extendsacross to the oppositewall of its respective arm and into engagement therewith at thebend 30,and a 1 wer section 35 at an angle to the intermediate section 34 andwhich extends downwardly toward the apex of the V in spaced relation tothe side walls of thearm.

The lower portion of the receptacle H contains a supply ofv mercury orother dispersible electrical conducting medium 36 which bridges theelectrodes l2 and I3 and thus completes and maintains an electricalconnection between the terminals 25 and 26 as long as the switch A is ina substantially vertical position. Due to the tubular shape of thereceptacle I I, it is necessary to use only a Very small amount'ofmercury. However, the amount is carefully measured because the height ofmercury in the arms 28 and 29' of the receptacle-determines the angle towhich the vehicle can. tilt before the electrical.

circuit; will be broken.

In order to permit the switch A to be readily mounted in an automobile,there ispermanently secured to the casing IS an encircling band 3Thaving laterally extending ears 38 and.39 provided with screw holes 46.The upper and lower ends of the casing- 10 are closed by plates 41 and42 respectively, and it is preferred that these be made non-removable toprevent tampering with the interior of the switch, although.

penings 43-and 44 are provided therein for reasonsto be more clearlyhereinafterset forth.

Aspointed out above, one of the features of my. invention is the factthat the automatic switch may be completely assembled,. adjusted 28 and29 respectively of the receptacle H. The.

open ends of the receptacle are then closed airtightly and the legsoftheretractible element sealed therein by means .of a suitable hardeningjsealing material 48; With the receptacle II closed inthis manner, themercury 36 therein will not only be prevented from escaping but,: in

addition, will be held from any movement during handlingof the switch bythe pressure of the air trapped within the arms 28 and 29 ofthereceptacle.

In installing the switch A in an automobile, it is preferably securedto. the engine side of the dashboard B by means of screws. 59 passingthrough openings Ml inuthe ears38 and'Sfi. Although not essential, it isdesired that the switch be positioned as nearly as is practicable to thecenter of gravity of the automobile so as to minimize the tendency ofcentrifugal force to retain the mercury 36 within the receptacle Iishould the vehicle turn completely over at high speed. After beingproperly mounted, the switch is interposed in the electrical circuit ofthe automobile, preferably in series with the line from the ammeter tothe coil, and this is accomplished by simply cutting the line and thenattaching the cut ends 5i] and El thereof to the terminals 2.5..and 26.

The switch may then be placed in operatin condition by grasping theupper end of the retractible element &5, which projects upwardlythroughthe opening 43 in the plate 4 I, and drawing'it up through theopening as shown in Fig. 2. The removal of the legs 46 and 41 from thereceptacle II will break the seal at the ends of the arms 28 and 23 andin order to facilitate a complete removal of the sealing material 48,the legstfi and 41 are-providedwith hooks or projections 52 on thelowerends thereof.

With the removal of the retractible element 45, the receptacle II willbev open to the at.- mosphere. However, the sharply inclined walls ofthe V shaped. portion of the receptacle and.

the restricted passageway 21 therein will act to baffle the movement ofthe mercury 36 to such an extent that itwill beretained in sub--stantially normal position during severe Vibratory motion, such as is.experienced in driving.

over extremely rough .roads; or against laterally applied centrifugalforce, suchas that resulting. :from rounding curves at high speed; butwill.

not affectthe tendency of the mercury 36 to flow freely under theinfluence of gravity, upon tilting of the vehicle to one side or. theother.

In other words, the' receptacle H has been so designed that themercury36 will be maintained in position'to close the electrical circuits.during all adverse'but non-dangerous operating conditions but willbepermitted to flowreadily out of normal position to open the circuits.should the vehicle show a tendency to upset by assuminga lateral tilt.

The action of the switch'n'during tilting of the vehicle in which it isinstalled can best be understood by, reference: to Figs; 4 and 5 hicleassumes alateral tilt to theright of more than ifixdegrees (this hasbeen'determined tobe a dangerous angle), the receptacle H of the.

switch A will assume the position shown in Fig. 4

which will cause theimercury 36 to flow into.

the :arm 29hr. the receptacle, and away-from theelectrode 52, to openthe electrical circuit and. As the engine stops, the.

turn oil the. engine. car will of course slowdown and should it thenregain an upright positionthe. circuit will be automaticallyreestablished andthe engine'again permittedto operate. However,shouldthe automobile lose its equilibrium and fall. onto its side orturn upside down, thereceptacle II will 7 pass throughthepositionshownin Fig. Sand the mercury will'fl'ow out through the endof' the arm29 and into the'casing.iil'from'which' it will discharge through oneof"the openings 43' and 4 1. The exhausting ofthe mercury 36 fromthe'switch will of course permanently break the circuits and they cannot again be closed without replacing the mercury. This will be the caseregardless of whether or not the Garcontinues to 'roll over and eventhough it-final-ly returns to-its normal upright position.

For example, when the Ve In connection with the reestablishment of theelectrical connection after a temporary opening of the circuits, it willbe noted that the ends of the electrodes 12 and I3 are flattened attheir lower ends to form a relatively sharp edge 53 which will quicklybreak the skin or surface tension of the mercury. On the other hand, thefact that the lower sections 35 of the electrodes l2 and I3 are spacedfrom the walls of the receptacle II will prevent any possibility of anaccidental connection between the electrodes after the mercury has beenexhausted by contact with a film of mercury on the receptacle walls.

In addition to providing protection from fires resulting from upsets, myinvention also contemplates the added feature of means for breaking theelectrical circuits in case of a serious collision in which the vehicledoes not overturn. As best shown in Fig. 6, this construction includes aswingably mounted weight or hammer 54 and an anvil 55 both arrangedwithin the casing H1 at opposite sides of the receptacle, II. The hammer54 is carried at one end of a strip of spring steel or the like 56secured at its op posite end to the inner wall of the casing ID as at51, so that as the hammer 54 swings to the right, it will strike thereceptacle II at about the apex of the V. The anvil 55 is fixed to theopposite wall of the casing l and so positioned that the relativelysharp edge 58 thereof is very near or in contact with both arms 28 and29 of the receptacle ll near the bend 30.

The length and resilience of the strip 55 is such that sudden stoppingof the vehicle or ordinary impacts will not swing the hammer 54 farenough to contact the receptacle I I. However, upon severe shock, suchas that resulting from a serious collision, the hammer 54 will be thrownagainst the receptacle II with suflicient force to break it on the anvil55 and spill the mercury 36 therefrom.

It will be noted from the above that in the event of either an upset ora collision, the electrical circuits to the motor will be instantly andpermanently broken by exhausting the mercury from the switch A. Thisfeature is an extremely important one because once an automobile hasturned over or sufiered excessive shock, the vapors from the gasolinespilled thereby will burst into flame or lead to an explosion, uponcontact with a spark from the electrical system or flame from theexhaust, even though the car is in an upright position at the time.Further, the fact that an element of the switch must be replaced, afteran upset or collision, before the ignition circuit can again be closedhas the additional advantage of preventing unauthorized persons fromdriving away a car, when injuries have forced the occupants totemporarily abandon it after an accident.

It is to be understood that the form of the in vention herewith shownand described is to be taken as the preferred embodiment of the same,and that various changes in the shape, size and arrangement of parts maybe resorted to without departing from the spirit of the invention or thescope of the subjoined claims.

I claim:

1. In an automotive vehicle including an electrical circuit, anautomatic safety switch interposed in said circuit comprising an openreceptacle formed of a tubular member having two spaced, substantiallyvertical arms communicating directly with the atmosphere at their upperend and a passageway connecting said arms at their'lower ends, a pair ofspaced electrodes mounted outside of said receptacle and extendingdownwardly one into each of the arms of said tubular member to supportthe same, and a measured amount of mercury within the receptacle andbridging said electrodes whereby the electrical circuit will bemaintained closed during normal operation of the vehicle but will beopened whenever the vehicle is tilted to a dangerous angle andpermanently broken should the vehicle tilt beyond such angle to a degreesuflicient to permit the mercury to flow from said open receptacle intothe atmosphere.

2. In an automotive vehicle including an electrical circuit, anautomatic safety switch interposed in said circuit comprising an openreceptacle formed of a substantially V shaped tubular member havingdiverging arms open at their upper ends and connected together at theirlower ends by a passageway at the apex of the V, a pair of electrodesmounted outside of said receptacle and extending downwardly one intoeach of the arms of said tubular member, each of said electrodes beingshaped to engage the walls of said arms in a manner to support thereceptacle but having their lower portions spaced from said walls, and ameasured amount of mercury within the receptacle and bridging saidelectrodes whereby the electrical circuit will be maintained closedduring normal operation of the vehicle but will be opened whenever thevehicle is tilted to a dangerous angle and permanently broken should thevehicle tilt beyond such angle to a degree sufllcient to permit themercury to flow from said open receptacle.

3. In an automotive vehicle including an electrical circuit, anautomatic safety switch interposed in said circuit comprising a casing,an open receptacle formed of a substantially V shaped tubular memberhaving diverging arms communicating directly with the atmosphere attheir upper ends and connected together at their lower ends by apassageway at the apex of the V, a pair of spaced electrodes carried bysaid casing and extending downwardly one into each of the arms of saidtubular member for supporting the same, and a measured amount of mercurywithin the receptacle and bridging said electrodes whereby theelectrical circuit will be maintained closed during normal operation ofthe vehicle but will be opened whenever the vehicle is tilted to adangerous angle and permanently broken should the vehicle tilt beyondsuch angle to a degree sufllcient to permit the mercury to flow fromsaid open receptacle into the atmosphere.

4. In an automotive vehicle including an electrical circuit, anautomatic safety switch interposed in said circuit comprising a casing,an open receptacle formed of a substantially V shaped tubular memberhaving diverging arms connected together at their lower ends by apassageway at the apex of the V and provided with upwardly and inwardlydirected extensions open at their upper ends, a pair of spacedelectrodes carried by said casing and extending downwardly one into eachof the arms of said tubular member, said electrodes being shaped toengage the walls of the tubular member in a manner to provide asupporting and retaining means therefor, and a measured amount ofmercury within the receptacle and bridging said electrodes whereby theelectrical circuit will be maintained closed during normal operation ofthe vehicle but will be opened whenever the vehicle is tilted to adangerous angle and: permanently: broken should the vehicletilt-'-beyond such angle tore. degree sufficient'toi permit 1 themercuryi'toflowifromsaidopenireceptacle.

5; In an" automotive:vehicle-including anielec= trical circuit; an:automatic safety: switch. inter posed in said' circui-tficomp-rising anopeni receptacle formed or T a tubulari member having two I spaced;substantially vertical-armscommunicat ing directly with the 'atmospliereat their upper" ends and a constricted I passageway of smaller crosssection than said. arms connecting the arms at their lower ends, a pairof'spaced electrodesarranged one within each-or said arms, an'cl'ameasured amount of mercury within thereceptacle" and bridging saidelectrodes whereby" the electrical circuit will lee-maintained closed;during" ends, a pair of spacedelectrodes arrangedonewithinzeach'ofsaid-arms, and ameasuredamount of mercury: within: the: receptacle: and:bridging said' electrodes whereby-the: electrical circuit 'will bemaintained closed fduringsnormal o-peration of' the vehicl'e but willbe? opened whenever the:

VehicIe -is tiIted to a dangerous angle and permanently broken shouldthe vehicle-tilt beyond such angle to-- a degree sufficient to permitthe mercury to -fibw from said open receptacleint'o the atmosphere:

7! Inan" automotive vehicle-including an elec-' tricalcircuit, anautomatic safety switch interposed-"in said circuit comprising-an-openreceptacle formed of a substantially V shaped tubular member having armscommunicating directly witntheatmosphere'at'tlieir'upper ends andconn'ectedtogether' at their lowerendsby aconstricted.passagewayxofflattened cross section at theaperofthev, apair of spvaced'electrodes arrangedone withineach of said arms, and ameasuredainountl'of mercury'within the receptacle and" bridgingsaidelectrodes whereby. the electrical circuit'will be'maintained closedduring normal-operation of the vehicle but will be opened whenever thevehicle istilted to a dangerous angle and permanently broken should'thevehicle tilt beyond-such angle toa degree sufiicient to permit themercury. to vflow from said open receptacle into the atmosphere"CLIFFORD E. DEARBAUGH.

